The present invention relates to the vehicle navigation technology, in particular, to a method for providing vehicle navigation information within an elevated road area and an apparatus for vehicle navigation capable of implementing the method.
Currently, the industry is paying more attention to an Intelligent Transportation System (ITS). As an important part of the ITS system, the vehicle navigation technology provides navigation information such as location, velocity, direction and geography on an electronic map in real time, so as to guide a driver to his destination more quickly and safely.
A typical vehicle navigation system comprises a navigation host and a display. An antenna built in the system receives wireless positioning signal transmitted from one ore more satellites orbiting around the earth, on the basis of which the vehicle location can be measured. The navigation host matches the location derived from the positioning signal with electronic map data to determine accurate position of a vehicle on the electronic map. On this basis, a variety of location-based services, such as driving navigation, route recommendation and information inquiry, are provided.
An elevated road is a bridge, road, railway or similar structure that is above the ground. It can divert traffic and improve transportation efficiency. Usually, the elevated road is built above a ground level road. This, however, brings about an issue on vehicle locating. In particular, because it is difficult to determine height variation of an object from satellite positioning signal, the satellite signal-based positioning method cannot differentiate between driving on an elevated road and driving on the ground level road thereunder. As a result, the accuracy of the navigation information is affected.
In view of the above, a method that can differentiate between these driving states is desirable.